/framework/lib/classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php
PHP | 82 lines | 33 code | 17 blank | 32 comment | 2 complexity | 932d5b72101bf4193a3f21ded7b3430c MD5 | raw file
Possible License(s): GPL-3.0
- <?php
- /**
- * PHPExcel
- *
- * Copyright (c) 2006 - 2011 PHPExcel
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * @category PHPExcel
- * @package PHPExcel_Shared_Best_Fit
- * @copyright Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel)
- * @license http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt LGPL
- * @version 1.7.6, 2011-02-27
- */
- require_once(PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/bestFitClass.php');
- /**
- * PHPExcel_Logarithmic_Best_Fit
- *
- * @category PHPExcel
- * @package PHPExcel_Shared_Best_Fit
- * @copyright Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel)
- */
- class PHPExcel_Logarithmic_Best_Fit extends PHPExcel_Best_Fit
- {
- protected $_bestFitType = 'logarithmic';
- public function getValueOfYForX($xValue) {
- return $this->getIntersect() + $this->getSlope() * log($xValue - $this->_Xoffset);
- } // function getValueOfYForX()
- public function getValueOfXForY($yValue) {
- return exp(($yValue - $this->getIntersect()) / $this->getSlope());
- } // function getValueOfXForY()
- public function getEquation($dp=0) {
- $slope = $this->getSlope($dp);
- $intersect = $this->getIntersect($dp);
- return 'Y = '.$intersect.' + '.$slope.' * log(X)';
- } // function getEquation()
- private function _logarithmic_regression($yValues, $xValues, $const) {
- foreach($xValues as &$value) {
- if ($value < 0.0) {
- $value = 0 - log(abs($value));
- } elseif ($value > 0.0) {
- $value = log($value);
- }
- }
- unset($value);
- $this->_leastSquareFit($yValues, $xValues, $const);
- } // function _logarithmic_regression()
- function __construct($yValues, $xValues=array(), $const=True) {
- if (parent::__construct($yValues, $xValues) !== False) {
- $this->_logarithmic_regression($yValues, $xValues, $const);
- }
- } // function __construct()
- } // class logarithmicBestFit